A LCM is mainly composed of a fluorescent tube, a light guide plate, a polarizing film, a filter plate, glass substrates, alignment films, liquid crystal materials, thin film transistors and so on. First of all, the LCM must project light using a backlight source, and the light will first pass through a polarizing film and then through liquid crystals. At this time, the liquid crystal molecules arrangement will change the polarization angle of the light spreading through the liquid crystal, and the light also must pass through a color filter and then another polarizing film. By changing the voltage value applied to the liquid crystal to control the light intensity and the color appearing finally, a combination of different tones can be shown on a liquid crystal panel.
A backlight module is one of critical elements for the LCM. Because the liquid crystal itself is unable to give out light, the backlight module functions to provide a light source with sufficient brightness and uniform distribution so that the liquid module can display images in a normal way. A backlight module consists of an array of backlight units, each of which corresponds to a pixel. Brightness of each pixel is controlled by driving voltage of its respective backlight unit. When displaying, a standard backlight driving voltage is applied to each backlight unit.
For the LCM, issues such as technical reasons or as various zero units failing to meet the design requirements in the design and manufacturing process will lead to a phenomenon of uneven light and dark appearing in the final product. The phenomenon includes, for example, light leak problem caused by an extrusion to the LCD flat panel due to structure parts production failing to meet the precision requirement for the design, shadow caused by the failure to meet a designed mixed light distance, bright-dark uniformity caused by a uneven optical diaphragm, and other undesirable phenomenon. The above problems can be completely solved by a solution in which the design is modified and the machining accuracy of zero unit is improved, but this kind of scheme will waste a lot of manpower, financial and material resources without achieving a desired actual result.
Therefore, a method, device and system is eagerly needed in the technical field, which make detection and brightness compensation for a large number of products using the optical characteristics of a liquid crystal panel by the way of image acquisition, image processing and circuit driving in order to eliminate dark region in products and consequently improve product yield.